While perlite is an affordable and helpful material in gardening, it also has its downsides. Since it’s a non-renewable material, many people like to use alternatives. Additionally, perlite doesn’t work well with clay and easily breaks down into a powder, which isn’t ideal.
Here are 14 of the best substitutes for perlite in gardening:
- Clay pebbles (hydroton)
- Horticultural sand
- Bark
- Gravel
- Peat moss
- Vermiculite
- Styrofoam
- Rice hulls
- Stone wool
- Aquarium rocks
- Pumice
- Coconut coir
- Biochar
- Pine needles
Let’s look at these perlite alternatives in more detail so you can decide which one is best for you and your garden.
1. Clay Pebbles (Hydroton)
Much like perlite, clay pebbles are also heated to a very high temperature which causes them to expand. They’re used for holding oxygen and moisture around plants, and they can be used alone or mixed with soil.
They’re a great way to drain moisture from plants because they’re highly porous. Not only that, but they also help to aerate plants by keeping the air circulating. Since clay pebbles have many pores and holes, it’s easy for air to flow through them.
You can easily reuse clay pebbles because of their rigid structure. Since these pebbles can’t break down as easily as perlite, they’re a perfect choice for people who want to minimize waste and costs. Just be sure to wash them before each use, and you’re good to go!
On top of the fact that you can use clay pebbles multiple times, they’re also quite affordable. They’re cheap and easy to make and are simple to use in gardening.
Although clay pebbles are a great alternative to perlite (for the most part), there are some downsides. One of the most significant downsides is their weight. They’re heavier than perlite, and some people may view this as an inconvenience.
Additionally, clay pebbles require adequate washing and rinsing before use; this can be time-consuming, and many gardeners see it as an inconvenience. If you don’t wash and rinse them correctly, the remaining dust can cause damage.
In general, clay pebbles are long-lasting, environmentally friendly, and easily accessible, which is why they’re a great alternative to perlite.
2. Horticultural Sand
Horticultural sand is another alternative to perlite because its primary purpose is to drain and aerate the soil. It’s very gritty and rough, and it’s made of materials such as granite and quartz.
Although it’s called sand, it isn’t the same as the sand that you find on the beach or in a children’s play area. Horticultural sand is much rougher than normal sand; normal sand would be too soft for drainage and wouldn’t work well.
Horticultural sand can be mixed with compost or other materials when planting seeds. It creates a well-drained environment and reduces the risk of too much moisture.
You can also use sand to loosen clay, which can be challenging using perlite. That’s not to say it’s not tricky using sand, but it does work a little easier. The sand works by making the soil more porous and allowing water drainage to occur more easily.
To do this, you need to pour sand over the soil and then incorporate it into the ground by digging. It’s also essential to ensure that you use enough sand because too little won’t have much effect. The ratio of sand to clay should be 1:2.
You can also use horticultural sand for grass in rainy climates. If the grass on your lawn is water-logged and too moist, using sand is a great way to absorb and drain the water.
If you’re looking to improve your clay or garden soil through drainage, airflow, or making it lighter, horticultural sand is undoubtedly a perlite alternative worth considering.
On the downside, horticultural sand can be pricey. Some people like to use builder’s sand as a cheaper alternative because it works primarily like horticultural sand. However, if you don’t mind spending the extra money, it’s worth the investment.
3. Bark
Bark is a cheaper alternative to perlite. Using bark as a soil drain is excellent for draining plant beds. Unlike sand, you can use any amount of bark you want, depending on how quickly you want the drainage to occur.
This means that you can use it more sparingly, thereby saving money, time, and effort.
Not only is bark fantastic for moisture control, drainage, and aeration, but it’s also a good choice for suppressing weeds in the garden. Bark is also helpful in colder weather because it insulates the plant beds while remaining aesthetically pleasing.
You can also use bark for container gardening. If you’re growing plants in a pot, using some bark mulch can help to keep the moisture at a controllable level.
So, if you’re looking to drain your soil and want the added functions that bark has, it might be a better alternative for you.
4. Gravel
Gravel is yet another alternative to perlite. Gravel and perlite are similar because they’re both in rock form, but they’re not entirely the same. One big difference is that gravel tends to be much heavier than perlite.
Gravel works at keeping the soil well-drained and aerated, just like perlite. Not only is it useful in these ways, but it’s also an esthetically pleasing aspect of a garden because of its decorative appearance.
The gravel is easy to spread around the soil and relatively easy to maintain. It’s widely used in construction and as a ground surface due to its water-draining capabilities, so it also works well in gardening as a drainer.
5. Peat Moss
Like perlite, peat moss drains water from the soil and promotes aeration. However, they also have their differences. Sphagnum peat moss is acidic, whereas perlite has a neutral pH. This means that peat moss is more suitable for plants that crave acidic substrates, such as blueberries and strawberries.
It’s not so ideal for plants that need a neutral or alkaline substrate. This can be seen as a negative because it limits the types of plants that you can use it with. However, most peat moss sold at gardening stores tend to have low acidity. Check the pH of peat moss before deciding what plants to grow in this medium.
Since peat moss is sterile, it’s a safe and healthy way to grow your plants. It’s also organic and doesn’t contain any added harmful bacteria or chemicals. Peat moss is a good choice for starter plants because of its lack of harmful additives.
One downside of this alternative is that peat moss isn’t renewable or cheap because you can’t reuse it, so people are beginning to move away from it. Perlite, on the other hand, can be reused if handled correctly. The lack of reusability is a significant downside of peat moss.
Another downside of peat moss is its lack of nutrients. Since there aren’t many necessary nutrients, it’s not as valuable as some of the other materials mentioned in the article. However, this shouldn’t pose much of an issue once mixed with other nutrient-rich materials.
It’s also on the more expensive side, so if you’re planning on using a lot of it, you should keep that in mind.
6. Vermiculite
Vermiculite is helpful for seed sowing and propagation because it keeps the soil well-drained and somewhat aerated. Much like perlite, it has a neutral pH and occurs naturally within the earth. It’s mined and then heated to a very high temperature, at which point it expands.
While perlite is usually white and popcorn-like in looks, vermiculite tends to be brown and flakier. When the little vermiculite stones begin absorbing water, they expand into worm-like shapes.
Vermiculite is spongier than perlite, and it absorbs more water. Since this is the case, it doesn’t offer as much aeration as perlite. So, you should only use vermiculite as a substitute for perlite if your plants need moisture.
If your plants don’t require much moisture, using vermiculite might damage them and cause root rot, which you certainly don’t want! Where perlite drains the water, vermiculite retains water. This is the most significant difference between the two.
Vermiculite works by retaining water and releasing it into the soil when it becomes dry. So, when it rains, the vermiculite soaks up the rainwater. Eventually, when the soil is dry, it releases water, thereby nourishing the ground quickly and effectively.
For long-term sustainability, vermiculite is excellent because it naturally maintains the soil’s moisture level by keeping it wet when it gets dry. However, if you use it with the wrong plants, they can get severely damaged and even die.
7. Styrofoam
You may be thinking, “isn’t Styrofoam used in construction?” Well, you’re not wrong. It may come as a surprise, but you can also use styrofoam in horticulture and gardening.
I don’t recommend using styrofoam in your gardening because there are much better and more eco-friendly options, but I thought it would be interesting to include it in this list.
Some gardeners have used styrofoam over the years to help with drainage and aeration, but it’s not the most effective solution. Styrofoam isn’t biodegradable, unlike perlite and many other materials. This means it stays in the ground for years and doesn’t go away or disintegrate.
It can also get blown around in the wind, which may cause pollution in the surrounding areas. Styrofoam also contains some chemicals that can damage the health of the soil if left unattended for too long.
You may even get confused because perlite and styrofoam look similar. Although technically, you can use styrofoam as an alternative to perlite, it should be at the very bottom of your list.
8. Rice Hulls
Unlike styrofoam, rice hulls are highly sustainable and favored among earth-conscious gardeners. Rice hulls aerate and drain water, and they’re also a renewable source. Since perlite isn’t renewable, rice hulls may be a better option if you’re worried about sustainability.
Sustainable gardening is becoming more and more popular as the years go by, and using rice hulls will help your garden sustain itself without the need for any added pesticides, chemicals, or materials.
Rice hulls are great at draining and soaking up water while keeping your garden organic and pure. Rice hulls also improve seed flow; if you’re planting different seed species, using rice hulls will help keep everything evenly distributed. Even if the seeds are of different sizes and weights, rice hulls will help to keep everything uniform.
Not only do rice hulls help with soil drainage and soakage, but they also help prevent soil erosion. Erosion occurs when the upper part of the soil gets displaced due to outside factors such as wind, snow, rain, and animals.
So, adding rice hulls to your soil can help prevent the inconvenient effects of soil erosion and are a great alternative to perlite.
9. Stone Wool
Stone wool comes from natural materials, so no added harmful chemicals are involved. Much like perlite, stone wool also doesn’t contain any nutritional value. Therefore, it needs to be mixed with other materials or mulches to give plants the required nutrients.
Not only does stone wool drain water quickly, but it also retains small amounts of water. This helps keep the soil and plants hydrated at a healthy level.
However, this can make it difficult to decipher when the soil needs watering, so it’s common for people to overwater the soil unknowingly when using stone wool.
Stone wool is reusable but needs to be cleaned thoroughly between uses. The best way to wash it is by boiling and rinsing it.
10. Aquarium Rocks
Aquarium rocks, also known as aquarium gravel, can be used in the soil for aeration and drainage. Mixing these rocks with the soil creates a mulch, which is appropriate for cooler climates as it can retain heat from throughout the day.
They can also be used in potted plants. Not only do they add a decorative element to the pot, but they also act as a drainage system. Since aquarium rocks add weight to the pot, they also help keep it secure and prevent it from tipping over.
Aquarium rocks usually come pre-washed, so you don’t have to worry about any unwanted dust or dirt damaging the soil and plants. They also come in various colors, so you can choose the colors that best match your plant or garden.
11. Pumice
Pumice is a highly lightweight volcanic rock, much like perlite. If you’re looking for a material that offers lots of drainage and aeration, pumice is another excellent option.
It has a neutral pH and manages to maintain the structure of the soil slightly better than perlite does. If you’re wondering why pumice maintains the structure of the soil better than perlite, it’s because pumice doesn’t decompose. It means that it keeps the soil structured and rigid.
Pumice is an excellent soil amendment. It needs to be mixed with other materials to work correctly. Since pumice doesn’t contain any nutrients, it should be combined with nutritional elements. These additional elements typically include compost, manure, or soil, for example.
If you want to absorb rainwater in your plants, you need to create holes around the soil and place the pumice within the gaps. It would be best to make these holes around the plant in a moat. Not only can pumice be used to drain water, but it can also drain other spillages such as toxic liquids or oils.
12. Coconut Coir
It may come as a surprise to you, but you can use the outside layer of coconut in gardening. So, not only do coconuts provide tasty and fresh coconut water, but their outer shells are also helpful!
Coconut coir degrades slowly, which helps maintain structure within the soil. It also helps to aerate the soil, and it can drain and hold a lot of water. Once the soil is dry and needs water, the coir will release it into the soil.
While it retains much-needed water for the future, it also removes unwanted water if there’s too much. This helps prevent the plant from getting drenched and subsequently dying. Therefore, coconut coir is an excellent soil amendment to use if you live somewhere with more rainfall.
Coconut coir is one of the most popular choices of soil amendments because of its water retention capabilities. It’s also highly sustainable and healthy for the soil and the planet, things that are becoming more important nowadays as we push towards a greener planet.
You can also mold coconut coir into a biodegradable pot. The coir fibers are compressed and made into the shape of a plant pot. Keeping the plants in these DIY pots creates proper air circulation, moisture retention, and adequate drainage.
13. Biochar
Biochar brings water and nutrients to plants and protects them from harmful bacteria and pathogens. Like other materials on this list, biochar feeds water to the plants as they dry out, which prevents a drought-like effect.
Biochar also attracts and retains much-needed nutrients, thereby giving the nutrients to the plants as needed.
Another reason biochar is a popular alternative to perlite is that it’s better for the environment. Biochar doesn’t release as much carbon as other materials, so using it in gardening helps to reduce the risks of global warming.
14. Pine Needles
There are different ways to use pine needles in gardening. Firstly, you can use them to create mulch for the soil. When used as mulch, they help the soil retain water and stop weeds from growing. They also protect the soil from erosion due to outside factors such as the weather, animals, and humans.
Pine needles decompose, but they do so very slowly. This means that your garden can reap the benefits of pine needles for a more extended period. Due to their longevity, it saves you time, effort, and money, while also keeping your soil well-structured.
Another way to use pine needles is by adding them to a compost mixture. Although they have low pH levels, they decompose rather slowly and don’t affect the overall pH of the compost. Instead, they help the compost remain light and airy, which is highly important for aeration.
Ensuring your soil is protected from severe weather conditions is essential for growing healthy plants, and pine needles are an excellent resource for that. When you lay pine needles over the soil, they retain moisture and keep the ground safe for essential bacteria to grow.
This maintains the fertility of the soil and keeps it fresh and healthy. If you live in a cold region, covering the ground with pine needles will protect it from freezing temperatures.
Similarly, if you live in a warm region with strong sunshine and scorching weather, putting pine needles over the soil should protect it from the heat.
Different Types of Soil Amendments
All of the materials and soil amendments mentioned in this article can be separated into two categories: organic and inorganic. According to the University of Colorado, organic amendments come from things that were once alive, whereas inorganic amendments are mined or man-made.
Examples of organic soil amendments include:
- Compost
- Sawdust
- Grass Clippings
- Straw
Examples of inorganic soil amendments include:
- Perlite
- Vermiculite
- Sand
It’s usually best to use organic amendments and materials whenever possible because they offer more significant benefits and are generally better for the environment. Organic matter and materials improve the soil’s aeration, water retention, and nutrient retention.
Therefore, when choosing a substitute for perlite, it wouldn’t hurt to look into organic options. Not only is it good for your plants and your soil, but it’s also good for the planet in general.
Determining Which Perlite Substitute You Should Choose
There’s no definitive answer to which perlite substitute is best. The material you should choose depends on the type of plant and the general climate in your region.
If you’re planting a plant that needs to retain lots of moisture, for example, then you should choose a material that keeps water, such as vermiculite. However, if you need a material that drains a lot of water but doesn’t retain much water, you should choose a different material.
Understanding your plants and the conditions that they need will assist you in choosing the correct material or soil amendment for your garden.
